1. Field of Invention
This invention relates to signalling devices and is particularly directed to means for indication the presence or absence of mail in the mailbox.
2. Prior Art
In general, mailboxes are formed of opaque material. Therefore, it is necessary to make a trip to the box and open it in order to determine whether or not there is mail in the box. While most mailboxes have a manually movable flag which can be erected to indicate that there is mail within the box for the mailman to pick up, this has little informational value for a resident as to when the mail has been delivered; furthermore, depending upon two different people to perform two distinct manual operations to convey information will inevitably be nondependable in a way avoided by a fully automatic operation. Moreover, mail deliveries are not made at precise times. Thus, mail at some addresses may be delivered anytime between 9 A.M. and 4 P.M. Hence, persons expecting important mail are often required to make frequent trips to the mailbox to determine whether the mail has yet come. If the mailbox is located a substantial distance from the house or in inclement weather, the necessity for making such a trip can be annoying and, if repeated trips are needed, the annOyance Can become greatly aggravated. FurthermOre, where the mail may be picked up by more than one person, there is no way for anyone to know whether no mail has been delivered or whether someone else has picked it up. Numerous signalling devices have been proposed heretofore to overcome these problems. However, many of the prior art devices have been complex to operate and expensive to produce. Furthermore, many of the prior art signalling devices have involved electronic mechanisms which do not survive well when exposed to weather and, hence, have been subject to repeated failures. Thus, none of the prior art mailbox signalling devices have been entirely satisfactory.